The present invention relates to a roofing product. More specifically, the present invention is directed to the combination of a tapered starter block and a tapered shingle combined in courses to form a roofing system for a pitched roof.
Roofing shingles that are used to provide a protective environmental barrier layer for a pitched roof typically fall into one of the following categories: asphalt, wood shake, slate and composite shingles. Asphalt shingles often have little structural rigidity and provide a look to a roof that is less natural than wood shake or slate shingles. Composite shingles, as well as wood shake and slate shingles, are somewhat rigid in nature and have increased thickness as compared to asphalt shingles. The appeal of composite shingles is that a roof may be formed to replicate a wood shake or slate roof while providing a highly durable roofing product that is often less expensive and lower maintenance than a comparable shake or slate roof.
When installing a shingled roof covering system on a pitched roof, a starter course, or row, is usually coupled to a roof deck along the eaves to form a base for the first course of full shingles. With asphalt shingles, the starter course may be composed of shingles that have been cut so that they have a shorter length than the standard shingle. The flexible nature of asphalt shingles allows the first course to overlie the starter course and flex downwardly over the back edge of the starter course to contact the roof deck underlying the roofing system just rearwardly of the starter course (i.e., towards the roof apex or ridgeline). Additional shingle courses are applied to partially overlap the previous courses as the roofing installer works their way up to the ridgeline.
Significantly more difficulty arises in the installation of semi-rigid to rigid shingles with a starter course. Wood shake or composite shingles, which have a more significant thickness and rigidity than asphalt shingles, may be cut into a starter course at an installation site, but such cutting is time consuming and labor intensive. In the case of slate shingles, such cutting may not even be possible without special tools.
Another issue is that more rigid shingles do not lie flat on the starter course while maintaining some contact with the roof rearwardly of such starter course. As can be seen in FIG. 1, a traditional roofing system of semi-rigid shingles includes a starter course 10 nailed to the eave 510 of a roof deck 500, a first course of shingles 15 coupled to the roof deck 500 and additional shingle courses 20 coupled to the roof deck 500 moving up the roof deck 500. Each shingle course 15, 20 may be coupled to the roof deck 500 either by nailing to the underlying course (e.g., starter course 10) and/or directly to the roof deck 500 rearwardly of the course. This configuration creates both an exposed gap 25 and a hidden gap 30. The exposed gap 25 is formed between the first shingle course 15 and the starter course 10, and becomes increasingly larger moving down the starter course 10 due to the angle at which each shingle 15 lies when contacting both the roof deck 500 and a back edge 35 of the starter course 10. The angle of lie of each shingle 15 also forms the hidden gap 30 between the respective shingle 15 and the roof deck 500. Though the installation of additional shingle courses 20 to overlie the previous shingle course, additional hidden gaps 30 are formed.
Both the exposed gap 25 and the hidden gap 30 create unique problems. The exposed gap 25 allows wind to provide a lifting effect on the shingles 15, potentially pulling them off of the roof deck 500 or causing a structural failure due to high stresses at the point of attachment of the shingle 15 with the roof deck 500 or starter course 10. By nailing down shingles 10 towards a forward edge 40 thereof, the exposed gap 25 could be largely eliminated. This would be disadvantageous, however, for two reasons. First, the downward bending of the forward region of the shingle 15 creates high stresses laterally across the shingle 15 above the back edge 35 of the starter course 10. Also, the nails used to secure the shingle 15 in the forward region would be directly exposed to the outside environment, creating both a pathway for moisture to penetrate the starter course 10 and the roof deck 500 and an undesired aesthetic effect. The overlying shingle course (e.g., course 20) could be lengthened to overlie the nailing location of the shingle 15, but with additional material expense and labor. With respect to the hidden gap 30, the relatively large height of the gap 30 positions only a small portion of the rearward region, or headlap, of the overlying shingle 15, 20 in contact with the roof deck 500. Large impact loads incident on the shingle courses, such as those used in Underwriters Laboratories, Inc's.® (“UL”) 2218 specifications, also knows as the Class 4 impact resistance test, create high stresses on the shingles above the hidden gap 30. The Class 4 impact resistance test is meant to replicate a hailstorm hitting a roof, but may also give an indication of the resistance of roofing products to impact loads from other objects (e.g., tree branches, persons walking on the roof, etc.). With the traditional roofing system arrangement shown in FIG. 1, the stresses of impact loading are concentrated laterally across the shingle 15, 20 where the shingle overlies the back edge of the underlying course (e.g., back edge 35). Because there is little surface area of the shingle headlap that is in contact with the roof deck 500, impact load distribution is poor across the shingle 15, 20, making it difficult to reduce the stress concentrations.
Therefore, it would be beneficial to provide a product that would eliminate exposed gaps 25 in a roofing system and reduce the stress concentrations in shingles due to the presence of a large hidden gap 30. Additionally, it would be beneficial to provide a product that accomplishes the above and that is usable with different types of shingles and capable of being produced in numbers.